When the screen does not allow all segments to be seen, it may be one of several faults:
- Bad connections of the lower zebras. The solution is to clean with contact cleaner the contacts in both circuit, keyboard and zebras; and if it continues to not working, then change the zebras.
- Bad connections of the lightly soldered screen pins. First you need to check with a flat screwdriver, pussing lightly to a side all pins, one by one. If any gives, then you will have to resolder it. A small solder will suffice. Normally there is no need to add more solder - the one already applied is enough. Make sure that contact is made by applying downward pressure to the pin with the flat screwdriver that you used to test it.
- Bad connection between the LCD and the screen driver. If the two previous steps have failed, you need to check this one to discard the last one. You need to:
- One of the two screen driving circuits gone bad. This typically results on half of the 10 digits not working. This tends to happen when someone burns the circuit by inserting A24 batteries instead of N-type, subjecing the circuit to 96 volts instead of 6. The only solution is to find a donor machine and replace the screen. Use a small soldering gun and help lifting the pins with the tip of a plier, one by one. To solder the new one, follow the procedure in the above paragraph.
New Repair kit for HP-41c battery bay and expansion portsProduct no.: Flex-PCBAdhesive circuit for the often damaged flexible PCB in the battery bay (and I/O ports) of the HP-41c range of calculators. Shipping included in price. |
Assembled HP-41c battery bay and expansion ports moduleProduct no.: Flex-PCB AssembledAssembled module for the often damaged flexible PCB in the battery bay (and I/O ports) of the HP-41c range of calculators. Shipping included in price for EU customers. New price: cheaper circuit translating to 10% lower price! |
New Zebra connector for HP41C repairProduct no.: Zebra PCBThis piece is for repair of HP41c full nut calculator, substituting the damaged or corroded zebra connector that links the main board with the processor circuit. New design. |
Assembled HP-41c battery bay and expansion ports module FlatProduct no.: Flex-PCB AssembledFlatAssembled module for the often damaged flexible PCB in the battery bay (and I/O ports) of the HP-41c range of calculators. Shipping included in price for EU customers. This is the FLAT version, when the screw head domes are broken and grinded down - see pictures. New price: cheaper circuit translating to 10% lower price! |